Excavator with teeth coupled for pivotal movement in opposite senses

ABSTRACT

An excavating bucket is provided with a ground penetration blade carrying a pair of teeth which are arranged to precede the blade as the blade enters the ground. The teeth are pivotally supported on the blade and locked together so that they are only capable of pivotal movement towards or away from one another and so cannot both pivot in the same sense at the same time. When the teeth are displaced by virtue of their reaction with the ground, from median positions about which they pivot, an actuation mechanism is triggered which drives the teeth in the sense in which they have been displaced until they reach their limit positions and then returns the teeth to their median positions.

United Sta Ranini teS Patent 1 June 17, 1975 SENSES [75] Inventor: Daniel G. Ranini, Varreddes, France [73] Assignee: Poclain, Oise, France [22] Filed: Apr. 23, 1974 21 Appl. No.: 463,395

[30] Foreign Application Priority Data France 73.17566 May 15, 1973 3,145,488 8/1964 French 37/141R 3,627,056 12/1971 Rogers 172/40 Primary Examiner-Clifford D. Crowder Attorney, Agent, or Firm-Mason, Fenwick & Lawrence [57] ABSTRACT An excavating bucket is provided with a ground penetration blade carrying a pair of teeth which are arranged to precede the blade as the blade enters the ground. The teeth are pivotally supported on the blade and locked together so that they are only capable of pivotal movement towards or away from one another and so cannot both pivot in the same sense at the same time-When the teeth are displaced by virtue of their reaction with the ground, from median positions about which they pivot, an actuation mechanism is triggered which drives the teeth in the sense in which they have been displaced until they reach their limit positions and then returns the teeth to their median 7 Claims, 3 Drawing Figures [56] References Cited V UNITED STATES PATENTS 1,878,037 9/1932 Vodoz 37/141 T UX Z F- l I F t 2/ 6 L. d

SHEET EXCAVATOR WITH TEETH COUPLED FOR PIVOTAL MOVEMENTIN OPPOSITE SENSES BACKGROUND or THE INVENTION 1. Field of Invention The present inventionrelates to ground excavation penetration working tools.

2. Description of the prior art Ground excavation working tools in the form of excavation buckets are known. Such buckets are provided with movable teeth to assist the penetration of the bucket into the ground. Means have been provided to vibrate the teeth so that as they enter the ground they are caused to impact the ground and breakup the material which they encounter.

Such excavation buckets require strong vibrating mechanisms which add to the weight of the bucket and also consume a large amount of power.

It is an object of the invention to provide an excavating bucket of reduced weight and which consumes less power.

SUMMARY or THE INVENTION According to the present invention there is provided a ground penetration working tool, comprising a blade intended to penetrate a mass of material, at least two teeth projecting from the blade, each said tooth being pivotable relative to the blade about an axis extending perpendicularly to the plane of the blade, coupling means for coupling the two teeth for synchronized pivotal movement in opposite senses, and actuating means operable to cause the teeth to pivot towards and away from one another.

According to the present invention there is provided an excavation bucket comprising a ground-engaging blade including two pivotal toothed members having teeth arranged to precede the blade as the blade enters the ground, means for constraining the teeth to make synchronous pivotal movements in opposite senses, and actuation means responsive to the deflection of the toothed members from mean positions about which they pivot to drive the members in the sense in which they have been deflected to the limit of their movement in that sense and thereafter to return the members to their mean positions.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2 the excavation bucket has a penetration blade 1 which forms an extension to one end of a generally C-shaped outer wall 2 of the bucket. The blade 1 has two openings 3 each of which houses a corresponding body member 4 carrying a pair of teeth 5. An arm 6 corresponding to each member 4 is pivoted on the wall 2 by means of a respective shaft 7; both shafts 7 being rigid with the wall 2. Each shaft 7 is aligned with a corresponding one of the openings 3 in the blade 1 and is engaged by a forked portion 8 in the body member 4. Each arm 6 is coupled to its corresponding body member 4 by means of a removable pin 9 which engages respective openings 10 and 11 in the body member 4 and the arm 6. In this manner, each arm 6 and its corresponding body member 4 are securely coupled together, the arm 6 forming the tail of the complete assembly and the body member 4 forming a removable part, which carries the wearing parts, namely the teeth 5.

Each opening 3 is delimited by upper 12 and lower 13 walls, which hold the body member 4 against motion in the vertical direction, and by two bosses 14 which limit the pivotal movement of each body member 4 in a horizontal plane.

A rod 16, of fixed length, is pivotally coupled at opposite ends thereof to corresponding arms 6 by means of respective shafts 17. The two shafts 17 lie on opposite sides of a common plane containing the axis of the shafts 7 and are located at an equal distance from the plane 15.

A hydraulic double-action jack 18 is coupled at opposite ends thereof to the two arms 6, by means of two shafts 19. A three-position distributor 20 is similarly coupled between the said arms 6, by means of two shafts 21. The shafts 19 and the shafts 21 all lie on the same side of the plane 15; the two shafts l9 lying the same distance from the plane 15. The shafts 19 both lie the same distance from the two shafts 21. As is indicated in FIGS. 2 and 3, the distributor 20 has a slide portion which is coupled to one of the arms 6, and a body portion which is coupled to the other arm 6.

A removable metal portection sheet 22 covers the area of the shafts l9 and 21 and, consequently, the area of the jack l8 and of the distributor 20. This sheet has been omitted in FIG. 2, for the sake of clarity.

The hydraulic control system for controlling the jack 18 and the distributor 20 is shown in FIG. 3. The system includes a two-position distributor 23, and a main pump 24 which is connected by a feed duct 25 to a fluid tank 26 and by an output duct 27 to the distributor 23. A duct 28 connects the distributor 23 to the tank 26, while two ducts 29'and 30 connect the distributor 23 to the cylinder of the jack 18 on opposite sides of the piston which lies in the cylinder. The chamber formed on one side of the piston will hereinafter be referred to as the large chamber 56 and the chamber formed on the other side of the piston will hereinafter be referred to as the small chamber 57, and is the chamber which contains the piston rod 31 of the jack 18. Flexible hoses 32 and 33 are used to couple the ducts 29 and 30 to the chambers.

Four flexible hoses 34, 35, 36 and 37 are connected to the three-position distributor 20. The hose 34 is connected to the output duct 38 of an auxiliary pump 39, which is connected to the tank 26 by its feed duct 40. The duct is connected to the tank 26 by a duct 41. The distributor 23 has two small guide ducts 42 and 43 which, are respectively connected to the flexible hoses 36 and 37 through ducts 44 and 45.

Ducts 46, 47 couple the feed tank 26 to respective ducts 44, 45. The duct 46 includes an adjustable throttle and a non-return valve 48 which only allows fluid from the duct 44 to escape to the tank 26. The duct 47 includes an adjustable throttle and a non-return valve 49 which allows fluid to pass through the duct only in the direction of from the duct 45 to the tank 26.

The three positions of the distributor 20 provide the following connections;

in the first position the hoses 34 and 37, are interconnected while the hoses 35 and 36 are blocked;

in the second position the hoses 34 and 36, are interconnected while the hoses 35 and 37 are blocked;

in the third or intermediate position the hoses 34 and 35, are interconnected while the hoses 36 and 37 are blocked.

The two positions of the distributor 23 provide the following connections;

in the first position, the distributor 23 establishes communication between the three ducts 27, 29 and 30, and blocks the duct 28; and

in the second position the distributor 23 establishes communication between the ducts 27 and 30, and between the ducts 28 and 29. I

When distributor 20 is in its first position, the output duct 38 of the pump 39 is connected to the jack 43 (through ducts 34, 37 and 45). The effect of this is to move the distributor 23 in its first position. When the distributor 20 is in its second position, the output duct 38 is connected to the jack 42 (through ducts 34, 36 and 44), and this causes the distributor 23 to move into its second position. Accordingly, the first and second positions of the distributor 23 correspond respectively to the first and second positions of the distributor 20.

it will be noted furthermore that, in whichever position the distributor 23 lies, ducts 27 and 30 will be maintained in communication; the duct 30 being connected to the small chamber 57 of the jack 18 through the hose 33. The pressurized fluid contained in this small chamber 57 acts on the piston in a sense to bring the ends of the arms 6 together and thus move the two pairs of teeth apart.

The large chamber 56 of the jack l8 communicates with the delivery duct 27 of the pump 24 when the dis tributor 23 is in its first position, and with the tank 26 (through duct 28) when the distributor 23 is in the second position. The pressurized fluid contained in the large chamber 56, acts on the piston to drive the ends of the two arms 6 apart.

It will be appreciated that for a given position of one of the body members 4 (or of the corresponding arm 6) the other body 4 (and also the other arm 6), can only occupy one corresponding position. Indeed, within the tolerances of the pivotal members, it will be observed that the pivotal axes of the shafts 7 and the hinging shafts 17 constitute the apices of a deformable quadrilateral, in which the lengths of two of the sides (between axes 7-17 on each arm 6) and the length of the diagonal (represented by the rod 16) are invariable.

It will also be appreciated that on the one hand the movement of one of the pair of teeth 5 in a direction parallel to blade 1, and away from the central area of the said blade for example, causes a reverse movement (towards the centre of the bucket) of the end of the corresponding arm 6 and that on'the other hand, by

of teeth 5;.In other words; thetwo pairsiof teeth 5, either 'rnove away "from 'eachother, and away from the central area of the.blade ,'fo'r move towards each other, and approach" the "central? area or the blade 1 1 The operation of the excavation. bucket will now be described-I 1 The movement'of t cket as, ,whole is carried out in a standard manner ,up-to thefpoint where its penetration blade is mad cit; st ongthe matrial to be excavated. If one of the teeth 5'meets a particularly hard spot, it will be observed in thefirst place that the deflection stress which it undergoes is not, at first, transmitted to the support of the bucket. The pivotal mounting permits the slight sideways movement of the tooth itself in the direction of least resistance.

In similar manner, each of the pairs of teeth 5 will tend to insert themselves into the gaps in the ground which form points of least resistance, even in the absence of hard spots.

Generally the reaction of the ground on one of the pairs of teeth 5 is on an average equal to and opposite in direction to that which the ground exerts on the other tooth 5. Thus on average the ground forces act on the teeth in the same sense as the coupling between the two pairs of teeth allow them to move together. The material is therefore, either divided by the external side edges of the pairs of teeth 5, or on the contrary pinched between the internal side edges of the pairs of teeth. The stresses acting on the teeth are taken up, eitherby the shafts 7 and 17, and/or by the bosses 14. The penetration forces of the bucket do not therefore, on the average, cause any lateral deflection of said bucket.

It will be readily appreciated that the improvement in penetration provided by the teeth is bound up with the ease with which the teeth 5, side-stepping the hard points, wend their way towards the areas of low resistance of the ground. This mode of operation is obviously different to that of a vibrating tooth, which does not side-step the hard spot but, on the contrary, breaks it on its first encounter with it.

The function and action of the jack l8 and of its bydraulic control circuit will now be considered. The hydraulic system described is unstable since the large chamber 56 is permanently connected, either to the tank 26, or to the output duct 27 of the pump24. Thus the jack 18 tends, either to retract under the action of the pressure of fluid in the small chamber 57, or to be extended under the action of pressure of fluid in the large chamber 56. Accordingly the relative positions of the arms 6 will vary and the pairs of teeth 5 will perform a movement producing a see-saw effect. The seesaw effect disintegrates the material, which makes the penetration of the teeth 5, even easier.

It will naturally: have been noticed that the bringing together of the shafts 21, and the separation of the pairs of teeth 5, will move the distributor 20 into its first position. This in turn causes the distributor 23 to be placed in its first position. As a result the large chamber 56 is supplied with pressurized fluid to cause the jack 18 to extend and, accordingly, tomove the shafts 21 apart (and draw the teeth together).This movement of the shafts 21 places the distributo'r 20.,Ein-its intermediate distributor back intoits first position or intoits second position. If the distrib utor -Z O moves to. its second position the distributor 23f'i's. causedto move to its second position.-The large ch-arribe 'r 56 is thenconnected to the tank 26, and the jack 18 is again retracted to bring together the shafts 21 (and move the pairs of teeth 5 apart). The above operation is then repeated.

The adjustable throttles 50 and 51 act to prevent the pressurized fluid fed by the pump 39 into one of the two jacks 42, 43, from returning to the tank 26 before having acted on the said jack, and act to resist the pressure of fluid from the other jack from which fluid is being emptied. These restrictions provided by the throttles create a damping effect on the distributor 23 and this damping effect is consequently transmitted to act on the movement of the teeth 5. The value of this damping effect can be adjusted by adjusting the throttles.

The above described excavation bucket has been found to suppress or, at least, provide a substantial decrease in the effect of shocks applied to the teeth 5 on the remainder of the machine. The mechanisms (the hingeing shafts, and other members) are therefore subjected to smaller stresses, and the driver of the machine can work with greater comfort.

The described excavation bucket requires smaller operating jacks than previously proposed buckets to provide the same penetration. Accordingly, the jacks employed can be lighter and, additionally, the payload of carried material can be greater than that of standard buckets.

Finally relatively low energy is required to set the teeth in motion. This energy is not a vibration energy (low beat frequency), and is applied to parts having low mass (teeth 5).

l claim:

1. In a ground penetration working tool,

a blade intended to penetrate a mass of material,

at least two teeth,

means pivotally securing each of said teeth to the blade about an axis extending perpendicularly to the plane of the blade so that each tooth projects from the blade, coupling means for coupling the two teeth for synchronized pivotal movement in opposite senses,

actuating means connected to the teeth and operable to cause the teeth to pivot towards and away from one another,

said actuating means includes a single driving element coupled to the said two teeth at points lying on the same side of a common plane containing the said pivotal axes of the two teeth, and wherein the coupling means comprises a rod of constant length pivotally coupled to the two teeth at two points lying on opposite sides of said plane.

2. In a tool according to claim 1 wherein the actuating means comprises a hydraulic jack.

3. In a tool according to claim 1, including a protective metal sheet covering at least partly the actuating means and the coupling means.

4. In a tool according to claim 1, wherein the penetration blade has two bosses for limiting the range of pivotal movement of each tooth.

5. In a tool according to claim 1, wherein each tooth comprises a tail portion which is pivoted on the penetration blade and which portion is coupled to the actuating means, and

a wearing part which constitutes the working part of the tooth and is detachably secured to the said tail portion.

6. In a tool according to claim 1, wherein the actuating means comprises a main source of pressurized fluid,

a fluid tank,

the said single driving member, the member comprising a piston member,

a cylinder having a fluid admission chamber for receiving fluid under pressure to drive the piston member from a first to a second position, and

return means for returning the piston member from the second to the first position,

a two-position distributor, which selectively provides the admission chamber with communication with said main source when in one position and with the tank when in the other position, and

an oscillator, which is coupled to the distributor to cause the driving member to pivot the teeth in a sense towards the mean positions about which they pivot.

7. In a tool according to claim 6, wherein the oscillator comprises an auxiliary source of pressurized fluid, first and second fluid-operated drive members respectively operable to drive the two position distributor into said one position and the said other position, and

a three-position distributor which is coupled to both teeth, and is movable to change into a corresponding one of three positions in response to movement of the teeth, the three-position distributor when in the first and second of its three positions respectively supplying fluid from the auxiliary source to the first and second fluid-operated drive members and when in its intermediate position, isolating both first and second drive members from the auxiliary source. 

1. In a ground penetration working tool, a blade intended to penetrate a mass of material, at least two teeth, means pivotally securing each of said teeth to the blade about an axis extending perpendicularly to the plane of the blade so that each tooth projects from the blade, coupling means for coupling the two teeth for synchronized pivotal movement in opposite senses, actuating means connected to the teeth and operable to cause the teeth to pivot towards and away from one another, said actuating means includes a single driving element coupled to the said two teeth at points lying on the same side of a common plane containing the said pivotal axes of the two teeth, and wherein the coupling means comprises a rod of constant length pivotally coupled to the two teeth at two points lying on opposite sides of said plane.
 2. In a tool according to claim 1 wherein the actuating means comprises a hydraulic jack.
 3. In a tool according to claim 1, including a protective metal sheet covering at least partly the actuating means and the coupling means.
 4. In a tool according to claim 1, wherein the penetration blade has two bosses for limiting the range of pivotal movement of each tooth.
 5. In a tool according to claim 1, wherein each tooth comprises a tail portion which is pivoted on the penetration blade and which portion is coupled to the actuating means, and a wearing part which constitutes the working part of the tooth and is detachably secured to the said tail portion.
 6. In a tool according to claim 1, wherein the actuating means comprises a main source of pressurized fluid, a fluid tank, the said single driving member, the member comprising a piston member, a cylinder having a fluid admission chamber for receiving fluid under pressure to drive the piston member from a first to a second position, and return means for returning the piston member from the second to the first position, a two-position distributor, which selectively provides the admission chamber with communication with said main source when in one position and with the tank when in the other position, and an oscillator, which is coupled to the distributor to cause the driving member to pivot the teeth in a sense towards the mean positions about which they pivot.
 7. In a tool according to claim 6, wherein the oscillator comprises an auxiliary source of pressurized fluid, first and second fluid-operated drive members respectively operable to drive the two position distributor into said one position and the said other position, and a three-position distributor which is coupled to both teeth, and is movable to change into a corresponding one of three positions in response to movement of the teeth, the three-position distributor when in the first and second of its three positions respectively supplying fluid from the auxiliary source to the first and second fluid-operated drive members and when in its intermediate position, isolating both first and second drive members from the auxiliary source. 